LSSTApplications  18.1.0
LSSTDataManagementBasePackage
pickleFits.py
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1 from lsst.afw.fits.fitsLib import MemFileManager, ImageWriteOptions, ImageCompressionOptions
2 
3 import lsst.afw.table
4 import lsst.afw.image
5 
6 
7 def reduceToFits(obj):
8  """Pickle to FITS
9 
10  Intended to be used by the ``__reduce__`` method of a class.
11 
12  Parameters
13  ----------
14  obj
15  any object with a ``writeFits`` method taking a
16  `~lsst.afw.fits.MemFileManager` and possibly an
17  `~lsst.afw.fits.ImageWriteOptions`.
18 
19  Returns
20  -------
21  reduced : `tuple` [callable, `tuple`]
22  a tuple in the format returned by `~object.__reduce__`
23  """
24  manager = MemFileManager()
25  options = ImageWriteOptions(ImageCompressionOptions(ImageCompressionOptions.NONE))
26  table = getattr(obj, 'table', None)
27  if isinstance(table, lsst.afw.table.BaseTable):
28  # table objects don't take `options`
29  obj.writeFits(manager)
30  else:
31  # MaskedImage and Exposure both require options for each plane (image, mask, variance)
33  obj.writeFits(manager, options, options, options)
34  else:
35  obj.writeFits(manager, options)
36  size = manager.getLength()
37  data = manager.getData()
38  return (unreduceFromFits, (obj.__class__, data, size))
39 
40 
41 def unreduceFromFits(cls, data, size):
42  """Unpickle from FITS
43 
44  Unpack data produced by `reduceToFits`. This method is used by the
45  pickling framework and should not need to be called from user code.
46 
47  Parameters
48  ----------
49  cls : `type`
50  the class of object to unpickle. Must have a class-level ``readFits``
51  method taking a `~lsst.afw.fits.MemFileManager`.
52  data : `bytes`
53  an in-memory representation of the object, compatible with
54  `~lsst.afw.fits.MemFileManager`
55  size : `int`
56  the length of `data`
57 
58  Returns
59  -------
60  unpickled : ``cls``
61  the object represented by ``data``
62  """
63  manager = MemFileManager(size)
64  manager.setData(data, size)
65  return cls.readFits(manager)
A class to contain the data, WCS, and other information needed to describe an image of the sky...
Definition: Exposure.h:72
Options for writing an image to FITS.
Definition: fits.h:219
def unreduceFromFits(cls, data, size)
Definition: pickleFits.py:41
Options for tile compression of image pixels.
Lifetime-management for memory that goes into FITS memory files.
Definition: fits.h:121
A class to manipulate images, masks, and variance as a single object.
Definition: MaskedImage.h:74
Backwards-compatibility support for depersisting the old Calib (FluxMag0/FluxMag0Err) objects...
Base class for all tables.
Definition: BaseTable.h:61